Abstract

Hypertension is one of the chronic non-communicable diseases which pose public health challenges in developing countries especially among black race, and excess weight gain has been found to be one of the predictors of hypertension. Conventional Body Mass Index (BMI) is limited in measuring the weight gain in individuals of all population groups and this gives the need for more reliable anthropometric index such as waist circumference, waist-to-hip ratio and waist-to-height ratio to measure body composition. This study evaluates the relationship between blood pressure pattern and body composition of the hypertensive outpatients who were attending University College Hospital, Ibadan, and Oyo State, Nigeria. The study design was descriptive cross-sectional involving ninety-two (92) hypertensive outpatients; 55 females and 37 males. A semi-structured, interviewer-administered questionnaire was used to interview the participants. The past three and the current participants’ Blood Pressure (BP) readings were assessed from their case files after the patients had consulted the physicians, and average BP was calculated for each patient. Weight (kg), body fat and visceral fat of the participants were measured by Automated Omron device. Height (m) measured with the use of stadiometer. Waist circumference (m) and Hip circumference (m) were measured with non-stretchable tape. Waist-to-height, waist-to-hip ratio and Body Mass Index were calculated. The hypertensive outpatients were 40.2% males and 59.8% females. Mean age of the male and female participants were 57.1 ± 13 years and 54.8 ± 13 years respectively. More than half (53.3%) of them had family history of hypertension (HTN) and some (41.4%) of them had been treating hypertension for five years while 49.5% had been on treatment for more than five years. Of all the patients, only 6.5% had normal BP, 44.6% had preHTN, 31.5% had stage 1 HTN and 17.4% had stage 2 HTN. Mean weight of the female and male patients were 73.45 ± 12.46 kg and 74.98 ± 12.52 kg respectively. Mean height of the female and male patients were 1.61 ± 0.06 m and 1.73 ± 0.09 m respectively. Waist circumferences of the female and male patients were 0.95 ± 0.16 m and 0.94 ± 0.10 m respectively. Waist-to-Hip Ratios (WHR) of the female and male patients were 0.96 ± 0.14 and 0.94 ± 0.10 respectively. Waist-to-Height Ratios (WHtR) of the female and male patients were 0.59 ± 0.09 and 0.54 ± 0.06 respectively. Body fat parentages of the female and male patients were 39.57 ± 7.51 and 22.53 ± 8.39 respectively. Visceral fat percentages of the female and male patient were 9.05 ± 3.05 and 9.65 ± 5.08 respectively. Resting Metabolism of the female and male patients were 1436.33 ± 143.65 and 1606.43 ± 187.97. Significant associations were observed between the age and diastolic blood pressure (p=0.001), between the weight-to-height ratio and systolic blood pressure (p=0.019) and diastolic blood pressure (p=0.032) of the patients; between body muscle of the patients and diastolic blood pressure (p=0.055). In conclusion, majority of the hypertensive outpatients had family history of hypertension. There was prevalence of prehypertension and stage 1 hypertension among the patients. Most of them were overweight, obese and had high abdominal adiposity which predicts risk of metabolic diseases such as diabetes and hyperlipidemia among the hypertensive patients. Significant relationship was found between waist-to-height ratio and systolic and diastolic blood pressures, and between age and diastolic blood pressure, and between body muscle and diastolic blood pressure.

Keywords

Blood pressure, Body composition, Hypertension, Outpatients.

Introduction

Hypertension is one of the chronic non-communicable diseases
which pose public health challenges in developing countries
especially among the black race where it is more prevalent
with early onset and clinically more severe [1]. It is an
established risk factor of cardiovascular disease, premature
death and devastating condition related to the cerebrovascular,
cardiovascular and renal complications [2,3].

As people increase in age, adults tend to be more physically
inactive and store fats in their bodies, which slow down
metabolism leading to the secretion of chemicals such as
cortisol, leptin and other hormones which are more likely to
cause obesity [4].

Excessive calorie intake, genetics, culture and lifestyle are
other predictors of increased body fat. Excess weight gain has
been found to be one of the predictors of hypertension and
body fat distribution predicts hypertension independently of
Body Mass Index [5,6].

Body composition is the relative amount of fat and fat free
mass of the body. Conventional Body Mass Index (BMI) is
limited in measuring the obesity and overweight in individuals
of all population group because it does not distinguish between
the lean muscle and fat mass and does not account for
important contributors to weight such as bone density and
blood volume [7]. Body Mass Index does not account for
ethnic difference in body composition and distribution of
excess fat [8].

Body composition of individuals is measured mostly by the
anthropometry indicators which predict the adiposity, lean
body mass and size [6]. This explains the reason for using
other anthropometric parameters such as waist circumference,
waist-to-hip ratio and waist-to-height ratio [9,10] in addition to
BMI to determine the body adiposity.

The study aimed to determine pattern of blood pressure and its
association to the body composition among the hypertensive
outpatients who attended Cardiology unit at University College
Hospital, Ibadan.

Materials and Methods

This study was descriptive cross-sectional in design, carried
out among the ninety-two (92) hypertensive outpatients
comprising of 55 females and 37 males who attended
Cardiology Clinic of Medical Outpatients in University
College Hospital, Ibadan, Oyo State, Nigeria. The University
College Hospital, (UCH) Ibadan is the premier tertiary hospital
and a reference health center for healthcare delivery in Nigeria.

A semi-structured, interviewer-administered questionnaire was
used to interview the participants. The past three and the
current participants’ Blood Pressure (BP) readings were
assessed from their case files after the patients had consulted
the physician, and average BP was calculated for each patient.

Weight (kg), body fat and visceral fat of the participants were
measured by Automated Omron device. Height (m) measured
with the use of stadiometer. Waist circumference (m) and Hip
circumference (m) were measured with non-stretchable tape.
Waist-to-height, waist-to-hip ratio and Body Mass Index were
calculated.

Blood pressure of the participants was classified into normal
BP, prehypertension, Stage 1 hypertension and Stage 2
hypertension according to the recommendation of the United
States Joint National Committee on Prevention, Detection,
Evaluation and Treatment of high blood pressure.

The classification of blood pressure control was based on the
European Society of Hypertension and the European Society of
Cardiology classification (ESH/ESC, 2013). The controlled
blood pressure was placed with systolic blood pressure reading
of less than 140 mmHg and diastolic blood pressure readings
of less than 90 mmHg [11].

The ethical approval for the study was obtained from the
Institutional Review Board, Institute of Advanced Medical
Research and Training (IAMRAT), University College
Hospital (UCH), the University of Ibadan, Ibadan.

Data collected were analyzed with the use of Statistical
Package for Social Science (SPSS) software, version 20.0.
Data were expressed as mean, standard deviation, frequency
and percentage. Chi square test was used to determine
association between variables and the gender while logistic
regression was determined to test the association between the
nutritional status, body composition, systolic blood pressure
and diastolic blood pressure. Level of significance was p<0.05.

Results

The study comprised of 40.2% male and 59.8% female
hypertensive outpatients who had mean age of 57 ± 13.26
years and 55 ± 13.39 years respectively. More than half
(50.2%) of the participants were aged 55 years and above.
Large numbers (85.9%) of them were married. Seventy-six
percent of the participants were either traders or retirees.
Statistical significance (p=0.017) was observed in the
occupational status of the participants (Table 1).

Characteristics

Male
(n=37)
n (%)

Female
(n=55)
n (%)

Total
(n=92)
n (%)

X2

P value

Age (years)

Mean (SD)

57.1 (13.26)

54.8 (13.39)

55.7 (13.32)

1.433

0.698

Range

23-79

21-82

21-82

21-37

2 (25.0)

6 (75.0)

8 (8.7)

38-54

12 (37.5)

20 (62.5)

32 (34.8)

55-71

17 (42.5)

23 (57.5)

40 (43.5)

≥ 72

6 (50.0)

6 (50.0)

12 (13.0)

Marital Status

Single

2 (5.4)

2 (3.6)

4 (4.3)

3.724

0.293

Married

34 (91.9)

45 (81.9)

79 (85.9)

Divorce/Separated

0 (0.0)

2 (3.6)

2 (2.2)

Widowed

1 (2.7)

6 (10.9)

7 (7.6)

Occupational Status

Artisan

1 (2.7)

3 (5.5)

4 (4.3)

10.248

0.017*

Trader

7 (18.9)

28 (50.9)

35 (38.0)

Civil servant

9 (24.3)

9 (16.4)

18 (19.6)

Retiree

20 (54.1)

15 (27.2)

35 (38.1)

Note: *P<0.05, SD- Standard Deviation.

Table 1: Socio-demographic status of the Patients.

Information on the medical history of the patients is presented
by Table 2. It was observed that more than half (53.3%) of the
participants had family history of hypertension and some (41.4%) of them had been treating hypertension for five years
while 49.5% of them had been treating it more than five years.

Health information

Male
(n=37)
n (%)

Female
(n=55)
n (%)

Total (n=92)
n (%)

X2

P value

Family History of hypertension

Yes

17 (34.7)

32 (65.3)

49 (53.3)

1.33

0.249

No

20 (46.5)

23 (53.5)

43 (46.7)

Year of Diagnosis

<1year

5 (62.5)

3 (37.5)

8 (8.8)

9.43

0.093

1-5years

14 (36.8)

24 (63.2)

38 (41.4)

6-10years

7 (25.9)

20 (74.1)

27 (29.4)

11-15years

1 (25.0)

3 (75.0)

4 (4.4)

16-20years

4 (80.0)

1 (20.0)

5 (4.5)

>20years

6 (60.0)

4 (40.0)

10 (11.2)

Presence of other ailment(s)
with Hypertension

Yes

19 (52.8)

17 (47.2)

36 (39.1)

3.881

0.049*

No

18 (33.1)

38 (67.9)

56 (60.9)

Patients’ Purpose of taking Medication

For Hypertension only

22 (33.3)

44 (66.7)

66 (71.7)

5.377

0.068

For Hypertension and other ailments

14 (56.0)

11 (44.0)

25 (27.2)

Not taking medication

1 (100.0)

0 (0.0)

1 (1.1)

Patients’ BP Control level

≤ 140/90 mmHg

15 (31.9)

32 (68.1)

47 (51.1)

2.755

0.097

≥ 140/90 mmHg

22 (48.9)

23 (51.1)

45 (48.9)

Note: *p<0.05.

Table 2: Medical History of the Patients.

Table 2 presents the medical history of the participants. It was
observed that large number (60.9%) of the patients had only
hypertension while 39.1% of them had additional ailments to
hypertension. Such ailments were; kidney diseases (13.0%),
diabetes (7.6%), heart diseases (2.2%), Respiratory disease
(2.2%), and other diseased conditions (such as arthritis, cancer,
eye defect, goitre, ascities, oedema, pile, hepatitis, GIT
problem) accounts for 14.1% (Table 3).

Table 3: Other Health conditions with Hypertension among Hypertensive Patients.

A statistical significance (p=0.049) was observed between the
patients who had only hypertension and the patients who had
hypertension with other diseases (Table 2). On medication,
71.7% of the patients took medications prescribed by the
physicians for high blood pressure only while 27.2% of the
patients took the medications for both hypertension and other
diseases and very few (1.1%) did not take medication as at the
time of the study.

The blood pressure pattern of the patients is presented by Figure 1. Only 6.5% (male=8.1%, female5.4%) of the patients
had normal blood pressure; 44.6% (male= 32.5%,
female=52.7%) had prehypertension, 31.5% of the patients
(male=18.9%, female=25.5%) had stage 1 hypertension and
17.4% (male=18.9%, female=16.4%) had stage 2 hypertension.
Half (51.2%) of the patients had their blood pressure controlled
while 48.9% of the patients had their blood pressure
uncontrolled (Table 3).

Figure 1:Pattern of Blood Pressure among the Hypertensive
Patients.

Table 4 shows the Body Mass Index (BMI) of the participants.
It was found that many (64.1%) of the patients were either
overweight (36.8%) or obese (27.2%). Overweight (64.7%)
and obesity (80.0%) were higher among the female patients
than among the male counterparts. The Body Mass Index
(BMI) of the patients was statistically significant across the
gender (p=0.006).

Body Mass Index (BMI) (Kg/m2)

Male
(n=37)
n (%)

Female
(n=55)
n (%)

Total
(n=92)
n (%)

X2

P value

18.5-24.99

20 (60.6)

13 (39.4)

33 (35.9)

10.299

0.006*

25.0-29.99

12 (35.3)

22 (64.7)

34 (36.9)

≥ 30.0

5 (20.0)

20 (80.0)

25 (27.2)

Note: *p<0.05.

Table 4: Body Mass Index of the Patients.

Table 5 presents the relationship between anthropometry index
and the blood pressure of the hypertensive patients. The mean
weights of the female and male patients were 73.45 ± 12.46 kg
and 74.98 ± 12.52 kg respectively. The mean height of females
was 1.61 ± 0.06 m and that of male patients was 1.73 ± 0.09 m.
Waist circumferences of the female and male patients were
0.95 ± 0.16 m and 0.94 ± 0.10 m respectively.

Visceral fat (%) of the female and male patients were 9.05 ±
3.05 and 9.65 ± 5.08 respectively. Resting Metabolisms of the
female and male patients were 1436.33 ± 143.65 and 1606.43
± 187.97. Significant associations were observed between the
age and diastolic blood pressure (p=0.001), between the waist to-
height ratio and systolic blood pressure (p=0.019); waist-toheight
ratio and diastolic blood pressure (p=0.032) of the
patients. Body muscle of the patients had significant
association with the diastolic blood pressure (p=0.055).

Discussion

Treatment of the modifiable risk factors of hypertension such
as dyslipidemia, abdominal obesity and diabetes is the primary
goal of hypertensive patients in order to reduce the long-term
risk of cardiovascular morbidity and mortality [15-17]. The age
of most (78.3%) of the hypertensive patients in this study was
within 38 to71 years, showing that both young adults and older
adults are suffering from high blood pressure. This supports the
results of the studies conducted by other researchers
[13,17,18].

This study found significant association between Diastolic
Blood Pressure (DBP) and age among the hypertensive
outpatients. It supports the findings in which it was reported
rise in diastolic blood pressure with increased age among the
Pakistan adults in the comparative study conducted among
three populations at Metrovill [19]. Tziomalos et al. observed
that the relationship between DBP at admission and outcome
appears to be more prominent in hypertensive patients and
higher DBP at admission predict in-hospital mortality in
patients with acute ischemic stroke. This shows the relative
effects of increased diastolic blood pressure among the
hypertensive patients [20].

Having more than half of the hypertensive patients in this study
with family history of hypertension, reveals that hypertension
is a hereditary disease which has been confirmed by many
studies in Nigeria and abroad [20-22]. However, this is in
contrast to the finding of Deji et al. [16] who reported that
family history was not a risk factor of hypertension among the
Yoruba adults in the similar study location, South-West,
Nigeria where our study was conducted.

It was observed in this study that about half of the hypertensive
patients in Nigeria had been visiting hospital for treatment
more than five years. The number of these patients (49.5%) is
greater than 25.8% reported by Deji et al. [16]. The increase
can be due to poor adherence of the hypertensive patients to
their medication or the patients engaging in lifestyles which
prevent adequate blood pressure control among the
hypertensive patients. It could also reveal the state of the health
system in Nigeria. Although, the level of blood pressure
control in this study shows that half of the patients had their
blood pressure controlled (≤ 140/90 mmHg), but it was evident that majority of the hypertensive outpatients who participated
were having prehypertension and stage 1 hypertension [23].

The prevalence of prehypertension (44.6%) observed in this
study was closed to the level (45.5%) reported by Chimezie et
al. in their cross-sectional study among adults in Umuahia,
South-East Nigeria; less than 58.7% prevalence observed by
Isezuo in Northern Nigeria and more than 37.2% reported by
Mengistu in Ethiopia; 32.3% reported by Hu L [5] in China
and 26.1% reported by Gyamfi et al. in Ghana [21].
Prehypertension has been reported to be the risk factor of
hypertension, cardiovascular mortality and morbidity, a 3.5-
fold increase in myocardial infarction, atherosclerosis, small
vascular damage, coronary artery calcification, vascular
remodeling, and left ventricular hypertrophy [24-27].
Prehypertension has been found to be strongly linked with the
family history of hypertension, dietary pattern, lack of
exercise, abdominal adiposity and markers of genetic predisposition
to high blood pressure including parental
hypertension or diabetes [12,28].

On the body composition of the hypertensive patients, many of
the patients who participated in this study had increased waistto-
height ratio, waist circumference, waist-to-hip ratio, Body
Mass Index, body fat and visceral fat more than the normal
recommendations for both male and female adults. This study
observed that many of the patients were overweight and had
abdominal adiposity. The association of abdominal adiposity
with cardiovascular and metabolic diseases such as Type 2
diabetes and hypertension had been observed by many studies
[29]. The excess weight and body fat observed among the
hypertensive patients can be due to the sedentary lifestyle
which many retirees and traders were known [15]. They tend to
sit down for long period of time without expending the calorie
consumed.

This study found significant association of systolic and
diastolic blood pressures with waist-to-height ratio and body
muscle. This is in agreement with the findings of Roberta et al.
who reported linear correlation between waist-to-height ratio
and blood pressure in their study which was conducted among
the factory male workers in São Paulo State, Brazil. Alena also
observed association between waist-height ratio and systolic
blood pressure in his cross sectional study conducted among
the migrants of Russian and Kurdish women in Finland [30].
Waist-to-height ratio has been found to be more sensitive to predict metabolic risk than BMI and to allow similar boundary
value for different ethnic groups. It has been found to be the
best anthropometric predictor of hypertension [31].

Conclusion

This study establishes that majority of the hypertensive
outpatients had family history of hypertension. There is
prevalence of prehypertension and stage 1 hypertension among
the patients. Most of the patients were overweight, obese and
had high abdominal adiposity which predicts risk of metabolic
diseases such as diabetes and hyperlipidemia among the
hypertensive patients. Significant relationship was found
between waist-to-height ratio and systolic and diastolic blood
pressures, and between age and diastolic blood pressure, and
between body muscle and diastolic blood pressure.

Limitation of this Study

The cross-sectional design of this study affects its causal
inference. This study was unable to assess the lifestyles (such
as, dietary intake, smoking, alcohol consumption, physical
activity and stress) of the hypertensive patients which could
predict the cause of excess weight gain and abdominal
adiposity which anthropometry measured. Further study is
needed to measure the lifestyles and biochemical parameters
(such as lipid profile and blood sugar) of the patients should be
measured to determine the risk factors of hypertension and
their relationship with prehypertension.

Recommendation

Hypertensive outpatients are advised to seek medical advice on
how to lose weight, see the dietitian for appropriate diet
regimen for their health condition, engage in appropriate
physical exercise, avoid intake of saturated fat and
psychological stress which could predispose them to adiposity.

Ejike, Chukwunonso ECC, Chinwendu E, et al. Obesity determined by different measures and its Impact on the health-related quality of life of young-adult Nigerians. Asian J Clin Nutr. 2015;7:64-75.

Caminha CST, Haroldo SF, Narithania SC, et al. Waist-to-height ratio is the best anthropometric predictor of hypertension, a population-based study with women from a state of northeast of Brazil. Medicine. 2017;96:102.

Ashwell M, Hsieh SD. Six reasons why the waist-to-height ratio is a rapid and effective global indicator for health risks of obesity and how its use could simplify the international public health message on obesity. Int J Food Sci Nutr. 2005;56:303-307.

Rockwood HRM, Howlett SE. Blood pressure in relation to age and frailty. Can Geriatr J. 2011;14:2-7.